U.S. Pat. No. 3,706,384 (384 patent) in claim 1 teaches the flow distribution through a plurality of inclined plates, lamellae or cells in parallel to each other by means of entering the water into the lowermost side of the plates, lamellae or cells and discharging the water at the uppermost portion of the inclined plates, lamellae or cells. The '384 patent teaches the extension of the lamellae or cells to limit horizontal flow across the inclined lamellae or cells, U.S. Pat. No. 6,676,832 ('832 patent) teaches the use of inclined lamellae among other structural features including a dual chamber configuration for the treatment of surface water run-off from a storm event.
U.S. Pat. No. 5,562,819 discloses a net to trap floatable debris matter from flowing water in a subterranean chamber having an inlet and an outlet for connection to an underground conduit such as a sewer or storm drain conduit. The apparatus further includes a sensing system for detecting and signaling when the net is full of debris. A multi-bag or netting system is further disclosed in which at least two nets or bags are in parallel such that one net may accommodate overflow when the other net or bag is being serviced to remove the trash from the apparatus. Some form of this disclosed apparatus would reduce the collection of the solids entry openings that lead to the settling surfaces of other device downstream from it.
Provisional patent application 61/603,393, (Confirmation No. 2368), filing date Feb. 27, 2012, discloses an arrangement of netting and inclined lamellae or cells that reverses the flow direction through the inclined cells from entry at the lower most section to the uppermost section of the inclined cells and discharges through dedicated orifices instead of over a weir.
In general, the above referenced prior art patents deal with the treatment of water in order to physically remove solids and/or trash from the inflow to release water for direct discharge or further treatment including filtering action or disinfection action, desalination action or biological media filters or surface filtration to remove dissolved solids, disinfect or otherwise improve the purity of the water. The means of solids removal is intended to be passive and entirely dependent on the gravity induced flow of the water through the apparatus. The dynamic forces are generated by the flow of the water either indirectly or directly aided by the force of gravity.
In the USA, surface water run-off quality is regulated by the Clean Water Act and affects the construction cost of any site improvement for which a “Storm water Permit” is required from the EPA. When it rains the natural terrain contours and area generate a flow volume and a flow intensity or a drain rate. The water flows to the passive water quality treatment device which in turn discharges to receiving waters, filters, basins, lakes, etc. Often the water treatment device must be located in a limited area because of the right of way conditions. Collection surfaces of the device are responsible for the pollutant separation from the water and in terms of removal efficiency; a device reaches high efficiency when more collection area can be placed above a given footprint.
Furthermore, it is cost efficient to use hydraulic performance indicators that promote low Reynolds Numbers which indicate laminar flow in a flow conduit and uninterrupted settling. It is also important to reduce device depth since excavation affects installation cost exponentially, especially in highly populated regions with high water tables, which is near the water edge and shore lines.
Functionally, it is important to reduce the water turbulence and head loss between the device inflow and outflow conduits. It would be very beneficial to have a device that enhances these efficiency concerns for the purification of drainage water in one self-contained device.